<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <!--
        width 设置元素(标签)的宽度
        height 设置元素(标签)的高度

        background 设置元素背景色或者背景图片
        background:gold; 设置元素的背景色,
        background: url(images/logo.png); 设置元素的背景图片
    -->
    <!-- <style>
        div{
            width: 100px;
            height: 100px;
            /* background: red; */
            background: url(./image/logo.png) no-repeat;
        }
    </style> -->

    <!--
        border 设置元素四周的边框
    -->
    <!-- <style>
        div{
            width: 100px;
            height: 100px;
            background: red;

            border: 10px solid royalblue;
        }
    </style> -->

    <!--
        分别设置四个边的：
        border-top 设置顶边边框
        border-bottom 设置底边边框
        border-left 设置左边边框
        border-right 设置右边边框
    -->
    <style>
                div{
                    width: 100px;
                    height: 100px;
                    background: red;
                    
                    border-top: 10px solid royalblue;
                    border-bottom: 10px solid royalblue;
                    border-left: 10px solid royalblue;
                    border-right: 10px solid royalblue;
                }

    </style>
</head>
<body>
<div>test</div>
</body>
</html>